Integrated circuits (ICs) are manufactured by transferring geometric patterns from photomasks to light-sensitive material known as “photoresist”. In particular, a geometric pattern is formed on a layer of photoresist on a semiconductor substrate by providing light through a photomask. The photomask includes a transparent layer that is partially covered with an opaque material. The portions of the transparent layer covered with opaque material block light, while the remaining uncovered portions of the transparent substrate allow light to pass there through, such that the light passing through the photomask transfers a pattern to the photoresist. After the photoresist has been exposed in this fashion, the photoresist is developed to selectively remove portions of the photoresist which were exposed to (or not exposed to) light, depending on whether the photoresist has a negative or positive tone. In some instances, the underlying wafer can then be etched with the patterned photoresist in place and the photoresist layer can be subsequently removed. Multiple patterned layers can be built up on the IC in this fashion to fabricate overall IC design.